The present invention relates to fasteners, and more particularly to fasteners used to secure items to panels. Specifically, the present invention relates to threaded fasteners designed to be secured to a panel.
Conventional panel fasteners provide a threaded nut, a bolt, a rod or other type of fastener that is engageable in registry with an opening in a panel of sheet material, such as rigid plastic, aluminum or sheet metal. A device is secured to the panel through engagement of the engaged panel fastener, and a corresponding fastener portion.
There are two main technologies used to secure panel fasteners to panels. The first is welding, used when the panels are aluminum or sheet metal. One problem of welding fasteners to aluminum is that a large capital investment is required in providing systems for accurately locating the fastener on the panel, and for consistently and completely welding the fastener to the panel.
In mass production applications, statistical process control (SPC) is employed to ensure consistent quality products. In the event a single weld fails or is otherwise found to be inadequate or unsatisfactory, the requirements of SPC call for the recalling or examination of all related and/or inventoried components that may suffer a similar deficiency or defect. Thus, a failed weld on a single panel fastener worth pennies can involve a disruption in manufacturing costing thousands of dollars. In addition, the cost of operating and maintaining a mass production welding operation is considerable.
The other main technology used to secure panel fasteners to panels is used to produce products known as Smak Nuts, clinch fasteners or Pierce fasteners, and are disclosed in U.S. Pat. No. 5,445,483. In this type of system, the panel fastener is forced into the panel opening, and causes yielding, also referred to as cold forming or deformation of the panel and/or the fastener to create a tight friction fit.
As is the case with welding, the latter technology also requires large capital investment, in this case taking the form of hydraulic presses to apply the pressure needed for pressing the fastener into the panel opening. Thus, there are high equipment and labor costs associated with securing panel fasteners to panels with Smak Nut, Pierce or clinch nut technology.
Another disadvantage of existing technologies used to secure panel fasteners to panels is that relatively low torque forces, measured in Newton Metres, are required to cause the fastener to become detached or disengaged from the panel. Where manufacturing process employs SPC, these technologies entail significant monitoring, evaluation and correction costs in the event of a failure.
Thus, a first object of the present invention is to provide an improved type of panel fastener technology which requires neither welding nor yielding of the panel or the fastener itself.
Another object of the present invention is to provide an improved type of panel fastener in which locking engagement of the fastener upon the panel is achieved merely by assembly of the fastener upon the panel.
Yet another object of the present invention is to provide an improved type of panel fastener which features relatively high torque failure values.
Still another object of the present invention is to provide an improved type of panel fastener which is installed using hand tools or automation.
The above-identified objects are met or exceeded by the present fastener and panel mounting system, which features a fastener with at least two extending lug formations which project beyond a periphery of the fastener body. On the panel, a like plurality of pocket formations or raised bosses or shear forms are configured and arranged to receive the lugs, and, as the fastener is rotated, lockingly retain the lugs so that the fastener is secured. In this manner, the fastener is securely held to the panel against significant rotational torque forces and without the drawbacks of welding or yielding, as in prior designs.
More specifically, a fastener is provided which is configured for engagement upon a panel having a panel opening, and constructed and arranged for engaging a mating fastener through the panel opening. The fastener includes a body having an axis of rotation, a peripheral edge, a main portion and a panel end. At least two lugs project from the peripheral edge at the panel end and are configured for being the points of fixed engagement with the panel without causing yielding of the panel or of the fastener.
In another embodiment, a fastener system is provided, including a fastener having a body with at least two lugs projecting from the body, a panel with an opening and at least two pocket formations disposed relative to the opening to receive the lugs and place the body in registry with the opening. The lugs are configured to lockingly engage the pocket formations as the body is rotated, the engagement being achieved without causing yielding the fastener or the panel.
In the preferred embodiment, each of the lugs is provided with an inclined or ramped upper surface to facilitate rotational sliding engagement with the pocket formations, and a lower surface with locking formations. Upon rotational engagement of the fastener with the pocket formation, the locking formation matingly engages an aperture defined by the pocket formation, to positively retain the fastener upon the panel.